We need to support petition against their paid content in the workshop.
Hopefully most of the mods will stay on Nexus which is much better site for Fallout and Skyrim mods.
Steam workshop isn’t so good (in my option) against Nexus because Steam workshop has their own installation which could destroy load order of your mods but in this video is it much better explained why Nexus is much better: Youtube.com

There is however, a petition in Change.org to remove the paywall on mods.
I'm guessing it'll need way more support than the (at the time of posting) 87k signatures, but it's worth a shot imo. It can show Valve in a quantifiable way their customers do not like this business model.
Seriously, was it that difficult to set up donation buttons? Steam already has account-bound money and all.